Switching assembly for an electrical musical instrument and percussive system therefor



April 11, 1967 w. L. FRITZ 3,313,878 SWITCHING ASSEMBLY FOR AN ELECTRICAL MUSICAL 7 INSTRUMENT AND PERCUSSIVE SYSTEM THEREFOR Original Filed March 30, 1964 2 Sheets-Sheet 1 5 W ALLEN, I

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April, 1967 w L FRlTz 3,313,878

SWITCHING ASSEMBLY'FO'R AN ELECTRICAL MUSICAL v INSTRUMENT AND PERCUSSIVE SYSTEM THEREFOR Original Filed March 50. 1964 2 Sheets-Sheet 2 4/ 39 1 I 39 I 42 I @i 0 4 Q/ 44 I I I I 43 /4 Fig.5 /4 Fig.6

INVENTOR. WILLIAM LFRITZ gnonnzvs,

United States Patent SWITCHING ASSEMBLY FOR AN ELECTRICAL MUSICAL INSTRUMENT AND PERCUSSIVE SYS- TEM THEREFQR William L. Fritz, Chatsworth, Califl, assignor to D. H. gildwin Company, Cincinnati, Ohio, a corporation of Continuation of application Ser. No. 355,621, Mar. 30,

1964, This application July 26, 1966, Ser. No. 573,438 Claims. (Cl. 841.01)

This is a continuation of application Ser. No. 355,621, filed Mar. 30, 1964, entitled, Switching Assembly for an Electrical Musical Instrument and Percussive System Therefor.

Theinvention relates to electrical musical instruments particularly of the organ type, and while not confined thereto, it achieves great utility in the provision of socalled percussive effects in connection with the pedal clavier of such instruments, and will be so described herein for the purpose of setting forth an exemplary embodiment.

Percussive effects, as that term is used herein, means the production of tones which simulate the tones of bells, bars, plucked strings and thelike, all of which tones are characterized by a decay at a given rate or rates when the playing keys are released. Percussive eifects are achieved generally through the use of gating circuit means characterized by a decay circuit including a capacitor and a resistor so related as to produce a tonal decay at the desired rate when a playing key is released. Needless to say, during the decay period at least, a source of electrical oscillations of the desired frequency must remain in connection with the gating means.

The term source of electrical oscillations as employed herein is intended to be broad enough to include mechanico-electrical generating devices, such as tone wheels or the like, a series or rank of electrical oscillators, one

circuit means after the release of the pedal key at least until the tone decay period has passed. Also, when a pedal key, upon actuation, has closed one of the aforesaid switches, and where provision is made for the switch to remain closed after the release of the pedal key, it is necessary to provide a means whereby the actuation of ing electrical oscillations having fundamental frequencies related to each other as the notes of the tempered musical scale. For use in connection with a pedal clavier, frequency-dividing means will be found advantageous and inexpensive, such means being driven by a series of oscillators in a main rank of oscillators for the manuals of the organ.

It is also possible, if desired, to employ, for pedal tone purposes, a variable frequency electrical oscillator and then to cause the oscillator to produce oscillations of the desired frequencies by appropriate tuning means conncted with switches actuated by the keys.

The action of gating circuits containing decay controlling means is well understood in the electrical musical arts, and is employed where percussive effects are desired. However, in the less expensive electrical musical instruments, it is a matter of substantial cost to provide a separate gating means of circuit for each of the semi-tones within the gamut of the pedal clavier. It has been proposed to employ, in connection with suitable sources of electrical oscillations, a single gating circuit rather than a plurality of them; and this becomes the more logical where only one of the pedal keys is likely to be actuated at any one time, or where the pedal portion of the instrument is essentially monophonic in nature.

But as will be evident, the sources of electrical oscillations not only must be connected selectively to the gating circuit means and through it to an output system by switches closed by the pedal keys respectively, but also the source must remain in connection with the gating a second pedal key so as to close its switch will result automatically in the opening of the key switch first closed. Yet again, if the release of the pedal key is to initiate the tone decay period of the gating means, yet another switch must be provided to de-energize, as it were, the gating means. This last mentioned switch is common to all of the pedal keys.

The requirements of a system of this character, as outlined above, has hitherto necessitated a complicated and expensive switching mechanism. For example, attempts have been made to provide latches in connection with the first mentioned switches, which will hold a switch in the closed position despite the release of the pedal key, together with means whereby the latch of the firstclosed switch will be released upon the actuation of another pedal key. The switch in connection with the last mentioned pedal key then becomes latched until yet another pedal key is depressed. Also, it has been suggested to provide a switch for controlling the gating means, which switch will be operated by a bail-like device overlying all of the pedal keys and actuable upon the depression of any one of them.-

It is an object 'of this invention to provide a switching means particularly for a pedal clavier which will meet all of the exigencies set forth above but which will be simplot and cheaper than any switching means hitherto devised.

It is an object of the invention to provide a switching means which can be used in connection with the keyboard, and particularly the pedal keyboard of an electrical musical instrument, not only to provide percussive effects, but also and with equal facility, to provide nonpercussive effects, all as will be explained herein.

These and other objects of the invention, which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these specifications, are accomplished by that certain construction and arrangement of parts of which an exemplary embodiment will now be described. Reference is made to the accompanying drawings wherein:

FIG. 1 is a partialtop plan view of a pedal clavier and switch assembly in accordance with the present invention.

FIG. 2 is a partial sectional view thereof taken along the section line 22 of FIG. 1, showing a pedal key in the unactauted position. FIG. 2 also contains a diagram- 'matic representation of circuit elements of one of the types mentioned, which may be used in connection with the pedal clavier and switch assembly.

FIG. 3 is a generally similar partial sectional view taken along the line 3-3 of FIG. 1 and showing a pedal key in the actuated position.

FIG. 4 is a partial elevational view showing the insulative panel, the flexible strand element and its supports together with certain pedal keys one of which is in the actuated position.

FIGS. 5 and dare respectively views of the individual supporting elements for the flexible strand, which elements are mounted on the insulative base.

Referring first to FIGS. 1 and 2, there is shown an abbreviated pedal clavier construction such as is employed 1 and a plurality of shorter pedal key elements 4 for the sharps and flats are mounted pivotally in known ways on key 3". The leaf spring serves not only as an effective pivot for the pedal key, but also as resilient means for returning the key to the unactuated position, determined in part by a felt or other sound deadening stop 8 at the rear of the base plate 1.

Each of the several pedal keys of the groups 3 and 4 is arranged to actuate a first switch so as to close it. An insulative panel 9 is supported above and in a plane substantially normal to the base plate by brackets 10, 11, 12 and 13 which, in turn, are bolted to a turned-over rear edge 1b of the base plate. At intervals along the length of the insulative panel 9, a number of insulative support elements 14 are affixed in spaced-apart relationship. These supporting elements are mounted by means of bolts and nuts 15 and 16 and are held away from the insulative panel by collars 17. The supporting elements will be such in number and so spaced that in eflect one of them will lie on either side of the median line of each longitudinal top edge of a pedal key; and also the supporting elements will be substantially evenly spaced throughout the length of the pedal clavier assembly.

The supporting elements 14 are perforated in the direction of the length of the insulative panel and are also grooved transversely as will later be described in more detail. A common strand-like element 18 passes through the holes in all of the supporting elements as indicated, and is'anchored at its ends as shown at 19 and 20. The strand-like element may take various forms. In theory it could be a single wire, or it could be a relatively narrow strip of flexible metal. However, solid continuous strand-like elements frequently have the disadvantage of developing fatigue when repeatedly bent or deflected. In the practice of this invention best results have been secured through the use for the strand-like element 18 of a thin coiled spring, the convolutions of which lie close together or in touching relationship. The spring may, if desired, be formed of beryllium-copper wire or of Phosphor bronze wire coated with silver. The object is to attain a strand-like element which is essentially incompressible in the direction of its length and which, if it has stretchability in the longitudinal direction, will be so diflicultly stretchable that the mutually exclusive feature, hereinafter described at greater length, will be attained. The strand-like element will, be of such length that, should it be deflected between any two adjacent ones of the supporting elements 14, it will tend to remain deflected at that point (see 21 in FIG. 4), but at the same time if deflected between another pair of supporting elements, it will be straightened out by tension between the first pair, as will now be readily understood.

When the strand-like element 18 is deflected, the deflected portion comes against a preferably flexible contact element 22 affixed to the insulative panel. The several contact elements 22 may be connected respectively to sources or circuits for providing electrical oscillations of fundamental frequencies corresponding to the semitones of the tempered musical scale, such as the source diagrammatically indicated at 23; and the strand-like element 18 may be connected to an output system 24 for the instrument or to a gating circuit means 25 in FIG. 2. It will be understood that once the switch parts, consisting of the strand-like element 18 and the contact element 22, come into the close-d condition as shown at 21, the switch will effectively remain closed until the deflection of the flexible strand element between another pair of the supporting means; and that the source of oscillations will be and will remain connected as described.

4 As will also be evident from FIG. 2, each key in the pedal assembly has a finger for deflecting the strand-like element 18. This finger, as shown, consists of a piece of wire 26 soldered or otherwise aflixed to a stud 27 in the playing key. The wire is bent upwardly and rearwardly as shown, providing a portion 28 in a position to contact the flexible element 18 as it extends between two I of the supporting means and to deflect it upwardly upon a continuation of the movement of the pedal key. sleeve 29 of insulative substance is placed on that portion of the wire at least which can contact the flexible strand.

Beyond the described upward extension of the wire, it

will be seen that the wire is bent downwardly as at 30, and that there is, again, a rearward horizontal extension 31. The insulative panel may be notched inwardly from its lower edge, as at 32 in FIG. 2, to prevent interference with the wire finger. At the rear of the insulative panel a continuous wire or bus bar 33 extends along behind all of the supporting means and is, itself, supported by studs 34 riveted into the insulative panel. The rearmost, horizontal portion 31 of the wire finger can be brought upwardly against the bus bar 33 when the key is actuated, as in FIG. 3;. It is preferred to place on the rearward extension 31 of the wire finger a short sleeve 35 of conductive rubber. The effect of this is to close the circuit between the parts 31 and 33 gradually, i.e. through a high but diminishing resistance, so as to avoid undesired surges of current.

The contact element 22 is quite flexible, and to this end it is preferably made of the same type of coated spring stock as is the strand-like element 18. The contact element 22 may be soldered to a grommet 35a riveted into the insulative panel 9 and the leads 36 from the oscillation sources 23 may be soldered to these grommets on the opposite side of the panel.

Portions of the wire elements extending forwardly along the keys from the studs 27 are interconnected by any suitable flexible conductor. This has been shown in the form of a flat braided metallic tape 37; but it may take other forms having suflicient flexibility to permit the actuation of a pedal key without affecting other pedal keys.

It will be evident from the disclosures above that the pedal clavier has been provided as to each key with a first switch (18, 22) for connecting sources of oscillations to a gating circuit 25, and with a second switch (31, 33) for an energizing circuit for the gating means 25. The first of these switches for each key form a series in which the switches are mutually exclusive, i.e. when one key such as the key 3 in FIG. 4 is brought upwardly,

its wire finger 26 will deflect the strand-like element 18 into the position shown in solid lines as at 21, thereby bringing the strand-like-element against the flexible contact 22. The effective length of the strand element is such, however, that if another key such as the key 4 is next actuated the strand-like element 18 will be deflected in a new position as shown in dotted lines in the same figure so as to close another switch. But since the strand is both substantially incompressible and diflicultly elongatable, the portion of the strand previously deflected by the actuation of the key 3 willpbe pulled downwardly into the horizontal position as shown in dotted lines thereby opening the first mentioned switch. Because of this arrangement the source of oscillations appropriate to the key 3 will be connected to the gating means 25 or the output means 24 upon depression of its key, but it will be disconnected upon the depression of any other key in the clavier. Thus the type of interference which would be encountered if two oscillatory circuits of different frequency were to be connected to the same lgating means is avoided.

Each key in the clavier also has a second switch which is closed when its key is actuated but unlike the first mentioned switch opens immediately upon the release of the key. The second mentioned switches for each key form a series in which the switches are connected in parallel by means of the element 37; and the last mentioned switch means are used to activate and de-activate the gating means 25. Gating circuit means are well known in the art and do not require illustration here. The flexible-conductor 37 has been shown as connected by a lead 38 to the gating means diagrammatically indicated at 25. The bus bar 33 which forms the stationary contact of the second mentioned switch means may be thought of as connected to a source of potential (not shown) or other means for activating or de-activating the gating circuit in known manner.

FIGS. 5 and 6 are respectively front and side elevations of the supporting means 14 for the flexible strand 18. The supporting means are blocks of insulative material configured so as to present lateral grooves 39 and 40 and a central ungrooved section 41. The ungrooved section is perforated as at 42 and 43 transversely so as to accept the bolts 15 described above. There is also a horizontal hole 44 through the ungrooved portion of the supporting means 14 to accept the strand-like element, not shown in FIGS. 5 and 6, but fully described above. The size of the strand receiving hole 44 is so related to the outside diameter of the strand-like element as to produce a slight frictional effect without producing in any sense a tight fit. Thus a tensional force applied to the strand-like element will cause it to slide within the hole 44 but will not tend to open up the convolutions of the strand-like element to any appreciable extent or at most to an extent which is well under the yield point of the metal. It may be found advantageous to bevel or countersink the ends of the hole 44 to avoid any sharp bending of the metal of the strand-like element when it is deflected between adjacent supports. The purpose of the grooves 39 and 40, which have a substantial depth, is to confine the deflection of the strand-like element to a vertical plane and to insure that it will be brought against the flexible contact element 22 upon actuation of the respective keys. As has already been explained, the strand when deflected between a pair of the adjacent supporting means 14 will remain in the deflected position until it is deflected at another point by the operation of another key.

It will be within the scope of the skilled worker in the .art to provide pedal clavier stop switch means for determining whether or not the output of the sources of oscillations will go through the gating circuit means on its way to the output means 24, using the term output means as inclusive of an appropriate electrical amplifier and one or more loud speakers. Also it will be consonant with the skill of the worker in this art to provide various tone color filters for modifying the timbre of the pedal tones, these filters (or other tone color modifying means) being controlled by pedal stop switches. The stop switches and tone color circuits have not herein been illustrated since they form no limitation on the present invention.

While the present invention has been described in an exemplary embodiment applied to a pedal clavier, it will be understood as applicable to other claviers of the instrument, particularly where mutually exclusive switch operation is desired. While each of the flexible contact elements 22 has been shown as connected to a single source of electrical oscillations, it does not constitute a departure from the invention to connect a plurality of harmonically related sources to each of the flexible contact elements 22 for the purpose of obtaining the effects of carillons supported on said insulative panel, a strand-like element extending through the perforations of said blocks and having a sliding fit therein, means anchoring the said strand-like element at its ends, said blocks being spaced respectively on either side of the median lines of the bodies of said keys, and means on said key bodies for engaging and deflecting the said strand-like element between adjacent blocks, the said strand-like element being diflicultly extensible and difficultly compressible in the axial direction, and of such length between said anchoring means that when deflected between adjacent blocks by the actuation of a key the said strand-like element will remain in the deflected position notwithstanding release of said last mentioned key until it is deflected at another point by the actuation of another key.

2. The structure claimed in claim 1 including a series of flexible contact means also mounted on said insulative panel, there being one such means lying between the several pairs of adjacent blocks, and so located as to be contacted by said strand-like element when said element is deflected.

3. The structure claimed in claim 2 wherein said strand-like element is in the form of a tight coiled spring of small diameter.

4. The structure claimed in claim 3 wherein said flexible contact means are also made from coiled spring metal, anchored at one end with respect to said insulative panel and free at the opposite end.

5. The structure claimed in claim 4 wherein said supporting blocks have grooves extending inwardly from their adjacent edges, said grooves lying in a plane substantially parallel to the plane of said insulative panel, said strand-like element lying partially within said grooves whereby the deflection of said element upon the actuation of a key is substantially confined to a plane parallel to the surface of said insulative panel.

6. The structure claimed in claim 5 wherein the said insulative panel on the side opposite the said supporting blocks carries a bus, and wherein the means on said keys for deflecting said strand-like element include means for making contact with said bus upon key actuation.

7. The structure claimed in claim 6 wherein the means .on the said key bodies for deflecting said strand-like element and for contacting said bus are metallic elements connectedtogether in parallel by a flexible conductor.

8. The structure claimed in claim 7 wherein said metallic elements are anchored to the key bodies, wherein they have a first portion for contacting and deflecting said strand-like element, and a second portion for contacting said bus, the first of said portions having a coating of insulation.

9. The structure claimed in claim 7 wherein said metallic elements are anchored to the key bodies, wherein they have a first portion for contacting and deflecting said strand-like element, and a second portion for contacting said bus, the first of said portions having a coating of insulation, the second of said portions bearing a covering of deformable resistive substance so as to make gradual contact with said bus.

10' The structure claimed in claim 9 wherein sources of electrical oscillations are connected with said flexible contact means, wherein said strand-like element is connected to gating circuit means, and wherein the switch means formed by the combination of said bus and said actuating means are located in the circuit for energizing and de-energizing said gating means. a

11. In combination with a series of actuable elements having bodies, an insulative panel extending in a direction transverse the said bodies, a series of perforated elements supported with respect to said insulative panel, a strandlike element extending through the perforations of said perforated elements, means anchoring the said strand-like element at its ends to said insulative panel, .and means on the bodies of said actuable elements for engaging and deflecting the said strand-like element between adjacent perforated elements, the said strand-like element being difliculty extensible and difliculty compressible in the axial direction and of such length between said anchoring means that when deflected between adjacent perforated elements by the actuation of an actuable element, the said strand-like element will remain in the deflected position notwithstanding its disengagement by said deflecting means on said last mentioned actuable element until it is deflected at another point by the actuation of another actuable element.

12. In a switching assembly, a series of spaced apart strand contacting supports, a strand-like element slidably engaged and supported at spaced apart points by said strand contacting supports, means anchoring said strandlike element at its opposite ends, a series of actuable elements movable relative to said strand-like element for engaging and deflecting said strand-like element between adjacent supports, said strand-like element being difficulty extensible and difficulty compressible in an axial direction and of such length between said anchoring means that when deflected by the actuation of a first of said actuable elements, the strand-like element Will remain in the deflected position until it is deflected at another point by the actuation of a second of said actuable elements, and contact means positioned to be contacted by said strandlike element when deflected by said actuable elements.

13. The switching assembly claimed in claim 12 wherein said strand contacting supports have openings therein, and wherein said strand-like element extends through the openings in said supports.

14. The switching assembly claimed in claim 13 wherein said assembly includes a base p'anel, wherein said strand contacting supports are mounted on said base References Cited by the Applicant UNITED STATES PATENTS 2,060,431 11/ 1936 Spicer. 2,625,070 l/l953 French. 2,953,649 9/1960 Deighton.

ARTHUR GAUSS, Primary Examiner.

D. D. FORRER, Assistant Examiner. 

1. IN COMBINATION WITH A CLAVIER HAVING PLAYING KEYS WITH BODY PORTIONS AND PORTIONS ARRANGED FOR ACTUATION, AN INSULATIVE PANEL EXTENDING IN A DIRECTION TRAVERSE THE BODIES OF THE PLAYING KEYS, A SERIES FO PERFORATED BLOCKS SUPPORTED ON SAID INSULATIVE PANEL, A STRAND-LIKE ELEMENT EXTENDING THROUGH THE PERFORATIONS OF SAID BLOCKS AND HAVING SLIDING FIT THEREIN, MEANS ANCHORING THE SAID STRAND-LIKE ELEMENT AT ITS ENDS, SAID BLOCKS BEING SPACED RESPECTIVELY ON EITHER SIDE OF THE MEDIAN LINES OF THE BODIES OF SAID KEYS, AND MEANS ON SAID KEY BODIES FOR ENGAGING AND DEFLECTING THE SAID STRAND-LIKE ELEMENT BETWEEN ADJACENT BLOCKS, THE SAID STRAND-LIKE ELEMENT BEING DIFFICULTLY EXTENSIBLE AND DIFFICULTLY COMPRESSIBLE IN THE AXIAL DIRECTION, AND OF SUCH LENGTH BETWEEN SAID ANCHORING MEANSD THAT WHEN DEFLECTED BETWEEN ADJACENT BLOCKS BY THE ACTUATION OF A KEY THE SAID STRAND-LIKE ELEMENT WILL REMAIN IN THE DEFLECTED POSITION NOTWITHSTANDING RELEASED OF SAID LAST MENTIONED KEY UNTIL IT IS DEFLECTED AT ANOTHER POINT BY THE ACTUATION OF ANOTHER KEY. 